What is the clinical evidence from this study?

Study design: RCT. Population: Healthy and mild asthma (n=26). Intervention: Ozone exposure vs. 0 ppb (clean filtered air). Primary outcome: Serum C-reactive protein (CRP) change at 24 hours (increase of 0.61 mg/L per 100 ppb, p=0.01).

April 11, 2015AJP Heart and Circulatory Physiology

Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects

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Key result

Short-term exposure to ambient ozone caused a dose-dependent increase in serum C-reactive protein by 0.61 mg/L per 100 ppb increase in ozone, alongside adverse changes in heart rate variability.

Why the study?

Does short-term exposure to ambient levels of ozone cause adverse changes in cardiovascular biomarkers in healthy adults?

Population

26 healthy adults, mean age 31.8, 50% female, with no history of cardiovascular, hematologic, or pulmonary…

Comparison

Inhalation of 100 ppb and 200 ppb ozone for 4… vs Inhalation of 0 ppb ozone for 4 hours with…

Design

RCT, The order of exposures was counter-balanced and randomized, The study…

Follow-up

24 hours post-exposure

Authors

MAMehrdad ArjomandiSan Francisco VA Medical Center HWHofer WongUniversity of California, San Francisco ADAneesh DondeSan Francisco General Hospital

Discussion

Member takes

Overview

Supports stricter ozone regulations to protect CV health; confirms inflammatory and autonomic mechanisms in healthy adults.

Study Design

Type

RCT (n=26)

Blinding

Double-blind

Randomization

Random order

Multicenter

Structured PICO

Does short-term exposure to ambient levels of ozone cause adverse changes in cardiovascular biomarkers in healthy adults?

Population

26 healthy adults and adults with mild asthma, aged 18 to 50 years, underwent 4-hour exposures to 0, 100, and 200 ppb ozone with intermittent exercise.

Intervention

Inhalation of 100 ppb (medium dose) and 200 ppb (high dose) ozone for 4 hours with intermittent exercise

Comparator

Inhalation of 0 ppb ozone (clean filtered air) for 4 hours with intermittent exercise

Outcome

Changes in biomarkers of cardiovascular disease including heart rate variability (HRV frequency domains), systemic inflammation (CRP, IL-6, IL-8), vascular volume and blood pressure control (ACE), and coagulability (fibrinogen, PAI-1) at 4 hours and 24 hours post-exposuresurrogate

Main Result

Mean Difference: 0.61

p-value: p=0.01

Short-term exposure to ambient ozone causes dose-dependent increases in sympathetic tone and systemic inflammation, providing a potential biological mechanism for ozone-associated cardiovascular morbidity.

Limitations

Small sample size
Timing of bronchoalveolar lavage measurements (only at 24 hours) may have missed earlier local inflammatory responses
Study may have been underpowered for the mediation analysis between systemic inflammation and autonomic responses
Four subjects withdrew from the study after the first exposure, meaning the final order of exposure assignments in the 22 subjects who completed all exposures was not fully counter-balanced.

Cite This Study

Arjomandi et al. (2015) conducted an RCT in Healthy and mild asthma (n=26). Ozone exposure vs. 0 ppb (clean filtered air) was evaluated on Serum C-reactive protein (CRP) change at 24 hours (increase of 0.61 mg/L per 100 ppb, p=0.01). Short-term exposure to ambient ozone caused a dose-dependent increase in serum C-reactive protein by 0.61 mg/L per 100 ppb increase in ozone, alongside adverse changes in heart rate variability.

synapsesocial.com/papers/6a86d36cddd5671cb07cb6bb https://doi.org/10.1152/ajpheart.00849.2014

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April 11, 2015AJP Heart and Circulatory Physiology

Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects

View Full Paper

Ask AI

Bookmark

Key result

Short-term exposure to ambient ozone caused a dose-dependent increase in serum C-reactive protein by 0.61 mg/L per 100 ppb increase in ozone, alongside adverse changes in heart rate variability.

Why the study?

Does short-term exposure to ambient levels of ozone cause adverse changes in cardiovascular biomarkers in healthy adults?

Population

26 healthy adults, mean age 31.8, 50% female, with no history of cardiovascular, hematologic, or pulmonary…

Comparison

Inhalation of 100 ppb and 200 ppb ozone for 4… vs Inhalation of 0 ppb ozone for 4 hours with…

Design

RCT, The order of exposures was counter-balanced and randomized, The study…

Follow-up

24 hours post-exposure

Authors

MAMehrdad ArjomandiSan Francisco VA Medical Center HWHofer WongUniversity of California, San Francisco ADAneesh DondeSan Francisco General Hospital

Discussion

Member takes

Overview

Supports stricter ozone regulations to protect CV health; confirms inflammatory and autonomic mechanisms in healthy adults.

Study Design

Type

RCT (n=26)

Blinding

Double-blind

Randomization

Random order

Multicenter

Structured PICO

Does short-term exposure to ambient levels of ozone cause adverse changes in cardiovascular biomarkers in healthy adults?

Population

26 healthy adults and adults with mild asthma, aged 18 to 50 years, underwent 4-hour exposures to 0, 100, and 200 ppb ozone with intermittent exercise.

Intervention

Inhalation of 100 ppb (medium dose) and 200 ppb (high dose) ozone for 4 hours with intermittent exercise

Comparator

Inhalation of 0 ppb ozone (clean filtered air) for 4 hours with intermittent exercise

Outcome

Main Result

Mean Difference: 0.61

p-value: p=0.01

Limitations

Small sample size
Timing of bronchoalveolar lavage measurements (only at 24 hours) may have missed earlier local inflammatory responses
Study may have been underpowered for the mediation analysis between systemic inflammation and autonomic responses
Four subjects withdrew from the study after the first exposure, meaning the final order of exposure assignments in the 22 subjects who completed all exposures was not fully counter-balanced.

Cite This Study

synapsesocial.com/papers/6a86d36cddd5671cb07cb6bb https://doi.org/10.1152/ajpheart.00849.2014

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

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